| /* |
| * Copyright (C) 2023 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package android.car; |
| |
| import android.annotation.Nullable; |
| import android.annotation.SystemApi; |
| |
| import java.util.concurrent.CountDownLatch; |
| import java.util.concurrent.TimeUnit; |
| import java.util.concurrent.TimeoutException; |
| import java.util.concurrent.atomic.AtomicReference; |
| |
| /** |
| * Synchronous implementation for {@link ResultCallback}. |
| * |
| * <p>Can be used to get the results synchronously where {@link ResultCallback} is required. |
| * {@link #get()} and {@link #get(long, TimeUnit)} methods can be used to get the result. |
| * |
| * @param <V> refer to a Parcelable object. |
| * |
| * @hide |
| */ |
| @SystemApi |
| public final class SyncResultCallback<V> implements ResultCallback<V> { |
| |
| private final CountDownLatch mLatch = new CountDownLatch(1); |
| |
| private AtomicReference<V> mResult = new AtomicReference<V>(null); |
| |
| /** |
| * Waits if necessary for the computation to complete, and then |
| * retrieves its result. |
| * |
| * @return the computed result |
| * @throws InterruptedException if the current thread was interrupted |
| * while waiting |
| */ |
| @Nullable |
| public V get() throws InterruptedException { |
| mLatch.await(); |
| return mResult.get(); |
| } |
| |
| /** |
| * Waits if necessary for at most the given time for the computation |
| * to complete, and then retrieves its result, if available. |
| * |
| * @param timeout the maximum time to wait |
| * @param unit the time unit of the timeout argument |
| * @return the computed result |
| * @throws InterruptedException if the current thread was interrupted |
| * while waiting |
| * @throws TimeoutException if the wait timed out |
| */ |
| @Nullable |
| public V get(long timeout, @Nullable TimeUnit unit) |
| throws InterruptedException, TimeoutException { |
| if (mLatch.await(timeout, unit)) { |
| return mResult.get(); |
| } |
| |
| throw new TimeoutException("Failed to receive result after " + timeout + " " + unit); |
| } |
| |
| /** |
| * {@inheritDoc} |
| * |
| * <p> |
| * This method should be called internally only. |
| */ |
| @Override |
| public void onResult(V result) { |
| mResult.set(result); |
| mLatch.countDown(); |
| } |
| } |